1. Technical Field
This invention relates to a control system for an automatic transmission applied to a vehicle, in particular, for controlling a driving force during cornering.
2. Prior Art
Various types of automatic transmissions have been offered to replace manual transmissions and automatically perform complicated operations of gear changes. The automatic transmission automatically operates the gear changes responsive to vehicle speed and accelerator opening. Judging to accelerate by large throttle valve opening, the automatic transmission operates to shift down to the forceful speed so that the rotational ratio of a drive and driven shaft is varied, while judging not to accelerate by small throttle valve opening due to release of the accelerator pedal, the automatic transmission operates to shift up to the forceless speed. However, the above conventional automatic transmissions equipped on vehicles are not sufficient, having problems as described below.
Upon passing through a curve safe and fast, a driver in the straight course slows down just before the curve based on the principle of slow-in fast-out, and then accelerates around the corner. With the aforementioned condition, the automatic transmission is automatically shifted down to the forceful speed to increase the driving force sharply, which results in deterioration of the cornering force for stable running, a decrease cornering in power of driving wheel, and may cause spin out in FR vehicles and drift out in FF vehicles due to wheel spin by decreased inner wheel load during cornering. Therefore, the above automatic transmission has a serious problem such as lack of safety. This problem is mostly found in recent high power engines which tend to generate too much driving force.